This move takes advantage of the fact that the black rook on f8 is horizontally pinned to the king. White is now threatening Qxg7#
Black will be forced to give up a lot of material in order to avoid the checkmate. Here’s the variations:
- 1. Ne6 Rg8 2. Qxg7# (The rook is still pinned.)
- 1. Ne6 Qxe6 2. Qxe6+-
- 1. Ne6 Bh6!? (An interesting way to defend the g7-square) 2. Nxf8 Nxf8 3. Rxa8
Note that 1.Rxa8 Rxa8 2. Re8+ Rxe8 3. Qxe8+ (threatening Nf7+) Qf8 4. Qxd7 is also good for white.